The expression refers to multiple columns. Multiple columns cannot be converted to a scalar value.

[proavinash]

please suggest a solution.

[DataNinja777]

Hi @proavinash ,

The error occurs because UNION() only accepts two tables at a time, but you're passing in three ADDCOLUMNS() results directly. DAX cannot interpret more than two tables unless you nest the UNION() calls. To fix it, you need to combine the second and third ADDCOLUMNS() calls using UNION() first, then combine that result with the first one. Here's the corrected version of your DAX:

MTD/QTD/YTD =
var TodayDate = TODAY()
var startyear = CALCULATE(STARTOFYEAR(SaleDump[Date].[Date]), YEAR(SaleDump[Date]) = YEAR(TodayDate))
var startquarter = CALCULATE(STARTOFQUARTER(SaleDump[Date].[Date]), YEAR(SaleDump[Date]) = YEAR(TodayDate), QUARTER(SaleDump[Date]) = QUARTER(TodayDate))
var startmonth = CALCULATE(STARTOFMONTH(SaleDump[Date].[Date]), YEAR(SaleDump[Date]) = YEAR(TodayDate), MONTH(SaleDump[Date]) = MONTH(TodayDate))
var result =
    UNION(
        ADDCOLUMNS(CALENDAR(startyear, TodayDate), "Selection", "YTD"),
        UNION(
            ADDCOLUMNS(CALENDAR(startquarter, TodayDate), "Selection", "QTD"),
            ADDCOLUMNS(CALENDAR(startmonth, TodayDate), "Selection", "MTD")
        )
    )
RETURN
    result

This corrects the structure so each UNION() has exactly two inputs and avoids the scalar value conversion error.

Best regards,

[proavinash]

SAME ERROR AGAIN.

[v-saisrao-msft]

Hi @proavinash,

Thank you for reaching out to the Microsoft Fabric Forum Community.

The UNION function returns a table as a result, so rather than creating a measure, try creating a calculated table.

Please refer the below Document:
UNION function (DAX) - DAX | Microsoft Learn

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